Stability and prognostic value of B-cell markers in primary SS: results from the French ASSESS cohort

To characterize the longitudinal evolution of B-cell biomarkers in patients with primary Sjögren's disease (SjD) and analyse their association with the clinical disease course.

We analysed data from the French multicentre prospective ASSESS cohort. Patients fulfilling AECG criteria with ≥2 visits including both immunological assessments and ClinESSDAI scores over a 5 years follow-up were included. Baseline B-cell biomarkers included immunoglobulin levels, monoclonal component, cryoglobulinaemia, complement fractions, RF and β2-microglobulin. Disease activity was assessed using ClinESSDAI score. Associations between the number of abnormal B-cell markers and disease activity were analysed using ANOVA and Kruskal-Wallis tests. Changes in IgG were evaluated according to the biological domain of the STAR index, defined as a relative decrease ≥10%.

Among the 395 ASSESS participants, 362 met inclusion criteria. Mean follow-up was 56.4 months (±10.6), with a mean of 5.3 visits per patient (±0.5). B-cell biomarkers remained stable in 80.5%. According to STAR criteria, 43.1% were classified as biological responders to the biological domain of STAR based on IgG decrease, occurring mostly within the first year, without correlation with changes in ClinESSDAI or ESSPRI. Although baseline ClinESSDAI did not differ by the number of B-cell abnormalities (P = 0.096), patients with multiple B-cell activity markers-particularly ≥5-had an increased risk of persistent or worsening disease (OR 4.6, 95% CI 1.2-17.8; P = 0.002).

B-cell biomarkers profile in SjD is largely stable over time. However, a high baseline 'B-cell burden' identifies patients at risk of poorer outcomes, supporting their use for stratification and monitoring.